1. Field of the Invention
This invention relates generally to pipe jacks and supports such as are typically utilized for support of pipe and other elongate members in horizontally oriented manner to facilitate welding and other operations. More particularly the present invention concerns a support mechanism having a support base structure that may be collapsible for ease of storage and handling and which is provided with quick-disconnect type removable support roll assemblies that have lateral spacing adjustment to accommodate pipes and other round objects of differing dimension and incorporate a brake to enable selective rotary positioning of a work-piece rotatably supported thereby. This invention also concerns pipe roll and support mechanisms having height adjustment to provide for selective elevation and rotatable support of loads and having a locking mechanism to ensure against inadvertent downward movement of the roll assemblies and the load supported thereby.
2. Description of the Prior Art
The term "pipe roll" as used herein is intended to mean support devices having roll assemblies to provide rotatable support for pipes, poles and any other object having a cylindrical outer peripheral surface and which is intended to be rotatably supported generally horizontally to enable various work to be performed on it. Various types of devices for rotatable support of pipe and various other elongate objects of round cross-sectional configuration have been developed. These support devices, typically referred to as pipe rolls and supports, generally comprise a support structure having legs and further having a roll support member at the upper portion on which is mounted a pair of rollers that provide rotatable support for the pipe or other object being supported. In some cases the roll assemblies of the support device are selectively positionable to enable the support device for efficient support of round objects of differing dimension.
Though pipe rolls are quite advantageous to the construction industry and commercial servicing industry to enable round objects to be efficiently positioned for the performance of work thereon, when pipe rolls are not being used they represent impediments in the work environment because they are difficult and inconvenient to store. Moreover, when pipe rolls are being transported or stored, they typically require considerable space because of their typically fixed geometry. It is considered desirable to provide pipe rolls that are collapsible so that, when they are not needed for rotatable support of work-pieces, they can be easily stored without requiring an unusually large storage facility. Also, pipe rolls that are collapsible can be more efficiently handled and shipped.
Many pipe rolls have selective incremental height adjustment by providing locking pins or bolts that are received within registering apertures in load elevating components. It is desirable to provide for selective height adjustment of rotatably supported loads wherein the pipe roll mechanism is quickly and efficiently adjustable to any selected elevation between maximum and minimum limits.
In many cases the load being rotatably supported by a pipe roll requires roll assemblies that are composed of a material that will not damage the cylindrical outer surface of the load. When specific roller material is required (rubber or polymer rollers for example) for rotatably supporting particular objects it is typically necessary to partially disassemble the pipe roll and replace the rollers of the roll assemblies. This is a time consuming and expensive process not only from the standpoint of labor, but also because of the rollers and other materials that are replaced and are often lost or misplaced so that they are not again usable. If the roll assemblies of pipe rolls are of adjustable to accommodate loads of differing dimension it is even more difficult and impractical to replace the rollers to accommodate rotatable support of particular objects. For these reasons, to provide for efficient support of differing work-pieces, it is considered more practical, though considerably more expensive, to provide different pipe roll devices for support of specific objects. It is desirable therefore to provide an adjustable pipe roll mechanism having roll assemblies that are simply and quickly interchangeable so that pipe rolls can be converted for efficient support of objects that require particular types of rollers to minimize the potential for marring or otherwise damaging the outer cylindrical surface of the object being engaged and supported by the rollers of a roll assembly.
Many types of pipe jacks are provided with friction type locking rings to facilitate a wide range of elevational adjustment between minimum and maximum work-piece elevations. In some cases, to achieve unlocking or release of lock rings, workers must release the load acting thereof and then manually manipulate the locking rings to the release positions thereof before the load is lowered. If the locking rings should slip for any reason or if the pipe jack should fall, there is potential for injury to the hands of the worker. U.S. Pat. No. 3,588,023 and U.S. Pat. No. 5,297,779 each provide apparatus that ensure protection for the hands and fingers of workers when the lock rings of pipe jacks are released. It is desirable therefore to provide pipe roll mechanisms with a lock ring unlocking system that ensures that the hands of the workers are always located away from the locking ring or rings as the lock rings are being moved to the unlocking or release positions thereof.